From Friday 9 to Sunday 11 December The Chocolate Festival is coming to London’s South Bank. Expect London’s master chocolatiers and a host of chocolate demonstrations. Edd Kimber, otherwise known as The Boy Who Bakes, is baking in the Chocolate Cookery Theatre, as is Allan Pickett, head chef at Plateau.

Here are their chocolate tips and a recipe from Edd:

Chocolate tips:

Allan Pickett, head chef at Plateau, (in the chocolate cookery theatre at 2pm on Friday 9 December) :

• Buy good quality chocolate. Something like an Original beans variety which is packed full of robust choccy flavours.
• Dont burn it. If you take dark chocolate over 60 degrees it will start to burn.
• Don’t be afraid to add a chunk of quality milk chocolate to your coffee. I love it as a little treat on a cold morning.
• Rather than use cocoa for dusting, why not use some finely grated chocolate – it will give such a hit of chocolate.

Edd Kimber (in the chocolate cookery theatre at 4pm on Saturday 10 December):

• If melted chocolate comes into contact with water it is likely to seize, becoming grainy and lumpy. Unfortunately, this can’t be recovered but don’t throw the chocolate away – you can add hot cream and use it as a ganache.
• If when making a ganache the mixture splits, you can recover it by using a hand blender to emulsify the mixture back into a smooth and silky mix.
• Use a good quality chocolate and bear in mind that percentages of cocoa are important but not necessarily a sign of quality. There is still a lot of terrible 70% chocolate around. For baking I recommend Green & Blacks because it is a good quality and widely available brand that has really good flavour and is very good to bake with.

Five minutes with Edd and a recipe for chocolate and chestnut torte:

Edd Kimber,  aka The Boy Who Bakes, won the BBC 2 series The Great British Bake Off in 2010. He has been involved with the Chocolate Festival for a couple of years and recently published a cookery book – The Boy Who Bakes by Edd Kimber (Kyle Books, £16.99) with photography by Yuki Sugiura.

He describes chocolate as his favourite ingredient to bake with. “It’s difficult at times, but chocolate is very versatile; you can make savoury dishes, make drinks with it.”

He’ll be baking a classic chocolate mousse with blackcurrant compote and double chocolate & sour cherry cookies on the day, but here is his recipe for chocolate and chestnut torte:

Chocolate and chestnut torte

“This is a surprisingly light chocolate cake – it looks decadent and rich but it’s actually melt-on-the-tongue light. Basically a cooked mousse, it has no flour but the subtle addition of chestnut adds a real depth to the cake. I prefer to serve this slightly warm with chestnut cream, but it can also be served chilled straight from the fridge.” Edd Kimber (see picture of the chocolate and chestnut torte, below)

Ingredients: (serves 18)

200g dark chocolate (at least 60–70% cocoa solids)
150g unsalted butter, plus extra for greasing
100g sweetened chestnut purée
100g light brown sugar
4 eggs, separated
50g caster sugar

For the chestnut cream

240ml double cream
100g sweetened chestnut purée

Preheat the oven to 180°C (160°C fan oven) gas mark 4. Line the base of a 23cm springform cake tin with baking parchment, lightly greasing the sides.

Set a heatproof bowl over a pan of lightly simmering water, making sure the bowl doesn’t touch the water. Add the chocolate and butter and allow to melt, stirring occasionally.

In a medium bowl, whisk together the chestnut purée, light brown sugar and egg yolks until thickened and pale.

Put the egg whites into a clean, grease-free bowl (this is best done using a freestanding electric mixer) and whisk until they form soft peaks. Then slowly pour in the caster sugar and whisk until the meringue is stiff and shiny.

Whisk the melted chocolate into the chestnut mixture, then mix in one third of the meringue. Gently fold in the remaining meringue, trying to knock out as little air as possible.

Pour the batter into the prepared tin and level gently. Bake in the preheated oven for 35-40 minutes or until the cake has risen and has a thin, cracked top.

Leave to cool for 10 minutes before removing the springform side, then allow to cool completely.

To make the chestnut cream, put the cream and chestnut purée into a bowl and whisk to combine. If you like a pouring consistency, serve it this way, but if you prefer it to be thicker, continue whisking until the cream holds soft peaks.